Code  Error Message and Description
12001 ERROR_INTERNET_OUT_OF_HANDLES
No more handles could be generated at this time.
12002 ERROR_INTERNET_TIMEOUT
The request has timed out.
12003 ERROR_INTERNET_EXTENDED_ERROR
An extended error was returned from the server. This is
typically a string or buffer containing a verbose error
message. Call InternetGetLastResponseInfo to retrieve the
error text
12004 ERROR_INTERNET_INTERNAL_ERROR
An internal error has occurred.
12005 ERROR_INTERNET_INVALID_URL
The URL is invalid.
12006 ERROR_INTERNET_UNRECOGNIZED_SCHEME
The URL scheme could not be recognized or is not supported.
12007 ERROR_INTERNET_NAME_NOT_RESOLVED
The server name could not be resolved.
12008 ERROR_INTERNET_PROTOCOL_NOT_FOUND
The requested protocol could not be located.
12009 ERROR_INTERNET_INVALID_OPTION
A request to InternetQueryOption or InternetSetOption
specified an invalid option value.
12010 ERROR_INTERNET_BAD_OPTION_LENGTH
The length of an option supplied to InternetQueryOption or
InternetSetOption is incorrect for the type of option
specified.
12011  ERROR_INTERNET_OPTION_NOT_SETTABLE
The request option cannot be set, only queried.
12012 ERROR_INTERNET_SHUTDOWN
The Win32 Internet function support is being shut down or
unloaded.
12013 ERROR_INTERNET_INCORRECT_USER_NAME
The request to connect and log on to an FTP server could
not be completed because the supplied user name is
incorrect.
12014 ERROR_INTERNET_INCORRECT_PASSWORD
The request to connect and log on to an FTP server could
not be completed because the supplied password is
incorrect.
12015 ERROR_INTERNET_LOGIN_FAILURE
The request to connect to and log on to an FTP server
failed.
12016 ERROR_INTERNET_INVALID_OPERATION
The requested operation is invalid.
12017 ERROR_INTERNET_OPERATION_CANCELLED
The operation was canceled, usually because the handle on
which the request was operating was closed before the
operation completed.
12018 ERROR_INTERNET_INCORRECT_HANDLE_TYPE
The type of handle supplied is incorrect for this
operation.
12019  ERROR_INTERNET_INCORRECT_HANDLE_STATE
The requested operation cannot be carried out because the
handle supplied is not in the correct state.
12020 ERROR_INTERNET_NOT_PROXY_REQUEST
The request cannot be made via a proxy.
12021 ERROR_INTERNET_REGISTRY_VALUE_NOT_FOUND
A required registry value could not be located.
12022  ERROR_INTERNET_BAD_REGISTRY_PARAMETER
A required registry value was located but is an incorrect
type or has an invalid value.
12023 ERROR_INTERNET_NO_DIRECT_ACCESS
Direct network access cannot be made at this time.
12024 ERROR_INTERNET_NO_CONTEXT
An asynchronous request could not be made because a zero
context value was supplied.
12025 ERROR_INTERNET_NO_CALLBACK
An asynchronous request could not be made because a
callback function has not been set.
12026  ERROR_INTERNET_REQUEST_PENDING
The required operation could not be completed because one
or more requests are pending.
12027 ERROR_INTERNET_INCORRECT_FORMAT
The format of the request is invalid.
12028 ERROR_INTERNET_ITEM_NOT_FOUND
The requested item could not be located.
12029 ERROR_INTERNET_CANNOT_CONNECT
The attempt to connect to the server failed.
12030 ERROR_INTERNET_CONNECTION_ABORTED The connection with the server has been terminated.
12031 ERROR_INTERNET_CONNECTION_RESET The connection with the server has been reset.
12032 ERROR_INTERNET_FORCE_RETRY Calls for the Win32 Internet function to redo the request.
12033 ERROR_INTERNET_INVALID_PROXY_REQUEST The request to the proxy was invalid.
12036  ERROR_INTERNET_HANDLE_EXISTS The request failed because the handle already exists.
12037  ERROR_INTERNET_SEC_CERT_DATE_INVALID SSL certificate date that was received from the server is bad. The certificate is expired.
 12038  ERROR_INTERNET_SEC_CERT_CN_INVALID SSL certificate common name (host name field) is incorrect. For example, if you entered www.server.com and the common name on the certificate says www.different.com.
12039  ERROR_INTERNET_HTTP_TO_HTTPS_ON_REDIR The application is moving from a non-SSL to an SSL connection because of a redirect.
12040  ERROR_INTERNET_HTTPS_TO_HTTP_ON_REDIR The application is moving from an SSL to an non-SSL connection because of a redirect.
  12041 ERROR_INTERNET_MIXED_SECURITY Indicates that the content is not entirely secure. Some of the content being viewed may have come from unsecured servers.
 12042  ERROR_INTERNET_CHG_POST_IS_NON_SECURE The application is posting and attempting to change multiple lines of text on a server that is not secure.
 12043  ERROR_INTERNET_POST_IS_NON_SECURE The application is posting data to a server that is not secure.
 12110  ERROR_FTP_TRANSFER_IN_PROGRESS The requested operation cannot be made on the FTP session handle because an operation is already in progress.
 12111 ERROR_FTP_DROPPED The FTP operation was not completed because the session was aborted.
12130  ERROR_GOPHER_PROTOCOL_ERROR An error was detected while parsing data returned from the gopher server.
 12131 ERROR_GOPHER_NOT_FILE The request must be made for a file locator.
12132  ERROR_GOPHER_DATA_ERROR An error was detected while receiving data from the gopher server.
12133  ERROR_GOPHER_END_OF_DATA The end of the data has been reached.
 12134 ERROR_GOPHER_INVALID_LOCATOR The supplied locator is not valid.
 12135  ERROR_GOPHER_INCORRECT_LOCATOR_TYPE The type of the locator is not correct for this operation.
12136 ERROR_GOPHER_NOT_GOPHER_PLUS The requested operation can only be made against a Gopher+ server or with a locator that specifies a Gopher+ operation.
12137  ERROR_GOPHER_ATTRIBUTE_NOT_FOUND The requested attribute could not be located.
 12138  ERROR_GOPHER_UNKNOWN_LOCATOR The locator type is unknown.
12150  ERROR_HTTP_HEADER_NOT_FOUND The requested header could not be located.
12151 ERROR_HTTP_DOWNLEVEL_SERVER The server did not return any headers.
 12152  ERROR_HTTP_INVALID_SERVER_RESPONSE The server response could not be parsed.
21531   ERROR_HTTP_INVALID_HEADER The supplied header is invalid.
12154  ERROR_HTTP_INVALID_QUERY_REQUEST The request made to HttpQueryInfo is invalid.
 12155 ERROR_HTTP_HEADER_ALREADY_EXISTS The header could not be added because it already exists.
12156   ERROR_HTTP_REDIRECT_FAILED The redirection failed because either the scheme changed (for example, HTTP to FTP) or all attempts made to redirect failed (default is five attempts).